CP contamination on Yamaha S 400-B

[Joe & Penny Goss]

This is a multi-part message in MIME format.

---------------------- multipart/alternative attachment
Hi Mark,
Is there any discoloration on the flange parts? It sounds like someone =
has used the graphite with an oil carrier to lube the center pins.
You might try removing the hammers and washing out the gunk.
Joe Goss
imatunr@srvinet.com
www.mothergoosetools.com
  ----- Original Message -----=20
  From: Mark Dierauf=20
  To: pianotech=20
  Sent: Friday, May 04, 2001 6:06 AM
  Subject: CP contamination on Yamaha S 400-B


    I had a customer complain about the touch on their Yamaha grand and =
discovered that it weighted off at 66 grams at middle C. When I checked =
the hammer flange I found that I could only get one swing, and that the =
bushings had a black residue on them. Closer inspection showed that this =
residue was also on the center pins as well as slightly in the wood =
surrounding the bushings. The residue on the pins themselves rubbed =
right off, and the pins looked shiny and new without any signs of =
buildup or corrosion. I repinned one to normal tolerances and the cloth =
felt as if it had normal resiliency, and the downweight dropped by 11 =
grams. I also found that the wippen flanges had the same residue, but =
hadn't seized up the way the the hammer flanges had. They seemed to be =
*slightly* on the tight side but still within normal tolerances (I =
didn't have my little spring gage with me). The jack & rep lever =
bushings were normal bright red cloth, and perfectly free.
    I have an appointment to return and repin this action, but before I =
do I wondered if anyone else has run across this before. Could this be =
something that Yamaha did at the factory? although I've certainly never =
seen it in their other grands, this is the first S series grand that =
I've serviced. The customer bought it used last year and so doesn't know =
it's history. Does anyone know of any center pin lubricants that react =
in this way? Is the problem likely to return after repinning? The serial =
# is: U3894763

  Thanks,=20
  Mark Dierauf

---------------------- multipart/alternative attachment
An HTML attachment was scrubbed...
URL: https://www.moypiano.com/ptg/pianotech.php/attachments/8a/f8/d6/b3/attachment.htm

---------------------- multipart/alternative attachment--